Which combination of tests would you use to confirm a ruptured urinary bladder in a foal?

• A. Chemistry, abdominocentesis, and peritoneal fluid creatinine
• B. Urinalysis only
• C. Abdominal radiographs
• D. Complete blood count

Answer: (A)

When a foal has a ruptured bladder, urine leaks into the abdominal cavity (uroperitoneum), and reliable confirmation comes from analyzing peritoneal fluid and comparing it to serum values. Abdominocentesis provides a sample of peritoneal fluid, and a chemistry panel helps characterize the systemic effects of urine absorption. The key diagnostic step is measuring creatinine in the peritoneal fluid and comparing it with serum creatinine. In uroperitoneum, the peritoneal fluid creatinine is higher than serum creatinine (often with a ratio >2), which directly indicates urinary leakage into the abdomen. This combination—peritoneal fluid sampling plus creatinine comparison and supporting chemistry data—offers the most definitive confirmation.

Abdominal radiographs can show fluid in the abdomen but are not as specific for bladder rupture. A complete blood count or urinalysis alone wouldn’t confirm uroperitoneum in this scenario.